My little brother has type 1 diabetes and was diagnosed with it at 12 months old and he sometimes get bad migraines. What causes migraines and bad headaches when you have type 1 diabetes?

He is 17 years old and is a big part of me. If something ever happened to him, damn I don’t know what I’d do.
I need some responses here guys.
He already has an insulin pump as do most people with type 1.